There is a growing interest in the convergence of the public switched telephone network (PSTN) and the various packet networks, such as the Internet. The convergence of these networks requires technology that facilitates interworking in a uniform and effective manner. The next generation of unified networks will provide an open and scalable architecture to accommodate multiple vendors and protocols under a common packet network. There have been significant strides to overcome the many obstacles to providing telephony services on a packet network with the same level of performance and availability as on the PSTN today.
The traditional PSTN provides constant bandwidth streams of information between users. These media streams travel over dedicated circuits, which have proven to be very reliable and capable of recovering from various failures in a fast and uninterrupting manner. Given the high quality levels associated with the PSTN, subscribers expect and demand traditional quality regardless of the transmission medium. Thus, both the packet networks and the interworking devices between the packet networks and the PSTN must provide high quality of service levels and be able to recover from communication or network failures in a fast and uninterrupting manner.
Of particular interest is the potential failure of interworking peripheral modules, which act as liaisons between the PSTN and the packet networks. Traditionally, failures in these interworking peripheral modules have led to dropped calls and unacceptable interruptions during the call. Accordingly, there is a need for an interworking peripheral module capable of quickly recovering from a failure in a manner eliminating or minimizing interruption in service and any noticeable break in speech, and avoiding dropping a call upon a failure.